Field of the Invention
Various embodiments of the present invention relate to a turbocharger; and, particularly, to a turbocharger generating a vacuum negative pressure, a vacuum negative pressure supply type brake system using the same, and a control method thereof which may make it possible to generate a vacuum negative pressure under a braking condition while maintaining an intake turbo charging function and to supply the generated negative pressure to the side of a brake.
Description of Related Art
In general, a brake system for a vehicle requires a vacuum negative pressure so as to assist a driver's pedal operating force and is configured to operate while interlocking with a surge tank provided at an intake passage through which a vacuum booster is connected to an engine.
Therefore, in case of braking based on a brake pedal operation, a master cylinder operates by a vacuum booster operating force assisted with a vacuum negative pressure at the side of the surge tank, so that a required brake hydraulic pressure may be generated when braking a vehicle.
However, a surge tank method may be influenced by the flowing speed of external air inputted into an engine, for which a required vacuum negative pressure may not be sufficiently generated when braking, depending on an engine operation condition. In particular, the lack of such a vacuum negative pressure may be worsened in a high compression ratio gasoline engine to which a turbocharger is applied.
For this reason, a high compression ratio gasoline engine separately uses a vacuum pump together with a surge tank in order to generate a sufficient vacuum negative pressure required when braking, so it becomes possible to maintain a required braking performance of a brake system with the aid of the above-mentioned configuration.
However, since the vacuum pump is configured to operate when it needs to supplement as much as the lack of a vacuum negative pressure required when braking, there may be a risk to increase the price of a vehicle due to the higher price as compared with its use frequency.
In addition, the vacuum pump is connected in front of a transmission (T/M) to a vacuum booster using a plurality of long vacuum hoses, which may cause an additional price increasing risk, and the degree of freedom in terms of the design of an engine room and a vehicle layout may be lowered.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.